Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 221827 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 227 PM EDT Sat Jul 22 2017 .SYNOPSIS... A cold front will remain just to the north and spark showers and thunderstorms this weekend. This front should push through the Mid Atlantic by Monday. High pressure will arrive to bring cooler conditions by the middle of the week. && .NEAR TERM /THROUGH TONIGHT/...
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As of 225 PM EDT Saturday... Scattered showers and thunderstorms have developed along the southern Blue Ridge, while the vast majority of the convection along the cold front to our north has remained well north of the CWA. The latest high resolution models only clip areas north of I-64 later this afternoon. Overall, POPs were reduced slightly in the early afternoon, but more adjustments will be made in the next update to account for how the convection evolves over the next couple hours. The heat and humidity continues to progress as expected in the Piedmont with heat indices crossing into the 100-105 degree range at this time. Highs were also slightly raised in response to the current temperature trends. It is possible for more rounds of convection to infiltrate the CWA overnight, so chance POPs were continued through tonight in VA/WV with slight chance POPs over NC.
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&& .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... As of 300 AM EDT Saturday... A couple of mesoscale convective systems will track across to the north along a frontal boundary from West Virginia and Maryland. An upper level trough will travel eastward over the Great Lakes Sunday as a broad upper level ridge remains over the Southeast. The tenacious upper ridge will keep the heat and humidity over the Mid Atlantic on Sunday with heat indices reaching over 100 degrees in parts of the Piedmont. With LIs of minus 4 to minus 6 and CAPE around 2,000 J/kg Sunday afternoon. SPC day 2 convective outlook placed most of the forecast area in slight risk for severe thunderstorms. There is the potential for damaging winds and possibly hail with stronger thunderstorms across the area. High temperatures Sunday afternoon will range from the lower 80s in the mountains to the mid 90s in the piedmont. Expecting convection to spread east Sunday night and taper off to a few showers overnight. Low temperatures Sunday night into Monday morning will vary from the mid 60s in the west to the mid 70s in the east. Depending on how well the convection can push the frontal boundary southward over our CWA will play a key role for Mondays forecast. Kept scattered showers and thunderstorms for Monday afternoon. The highest chance appears to be along the southern Blue Ridge and through the northwest North Carolina mountains. High temperatures Monday will be a couple of degrees cooler than Sunday with readings from around 80 degrees in the mountains to the lower 90s in the piedmont. Drier air moves in Monday night as high pressure approaches from the north. Low temperatures Monday night into Tuesday morning will generally be from around 60 degrees in the northwest mountains to the lower 70s in the Piedmont. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 330 PM EDT Friday... High pressure should build over the Northeast by Tuesday. The frontal boundary will be shoved southward southward toward the North Carolina coast by this time. Lingering moisture may still spark a few diurnally-driven showers and thunderstorms during each afternoon through this period. The best chances appear confined to the VA/NC border on Tuesday, but more potential exists for Wednesday with easterly to southeasterly flow from high pressure offshore. There could be some wedging possible east of the Blue Ridge, so high temperatures were pushed downward for Wednesday to allow for the potential of upslope flow along the Blue Ridge and more cloud cover. Temperatures should bounce back upward by Thursday as high pressure heads further out into the Atlantic Ocean. Long range models hint at another frontal boundary approaching our CWA by Friday. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/...
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As of 210 PM EDT Saturday... Scattered showers and thunderstorms will continue to develop over the remainder of the afternoon. The most organized convection should stay to the north, but the chances are good enough to keep VCTS for all TAF sites except DAN. Confidence is not high enough yet to mention thunder more strongly, but amendments will be made if needed through the afternoon. Otherwise, VFR conditions should persist outside of the showers and thunderstorms. There is a threat for severe weather, so turbulence will be an issue this afternoon. Another cluster of showers and thunderstorms could arrive overnight toward early Sunday morning near BLF and LWB, but confidence is too low to mention in the TAFs at this point. High clouds from convective debris upstream and a breeze through the night in the mountains will not permit fog to form. Scattered low clouds were kept for BLF and LWB due to the potential for MVFR ceilings. Ceilings and visibilities should be VFR during the day with winds starting to gust from the west just past 18Z on Sunday afternoon. Aviation Extended Discussion... Confidence is growing for the potential of a rather active period for Sunday afternoon and Sunday night. A cold front will be passing overhead, which should spark clusters of showers and thunderstorms. The models shift the front toward North Carolina by Monday with the potential for convection developing in the afternoon along the VA/NC border. However, most locations should remain VFR outside of the convection. Another cold front could push some of the moisture eastward by Tuesday, but high pressure may possibly wedge southward on Wednesday to create the possibility for MVFR/IFR ceilings. Conditions should return to VFR by Thursday as the weak wedge erodes quickly.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...Heat Advisory until 7 PM EDT this evening for VAZ044>047-058- 059. NC...Heat Advisory until 7 PM EDT this evening for NCZ005-006. WV...None. && $$ SYNOPSIS...PW NEAR TERM...PW SHORT TERM...KK LONG TERM...PW AVIATION...PW is the U.S. government's official web portal to all federal, state and local government web resources and services.